1. Field of the Invention
The present invention relates to a duplex printing apparatus for effecting printing on both sides of one sheet of recording paper.
2. Description of the Related Art
Conventionally, a printing apparatus is known for effecting so called duplex printing in which images are formed on both sides of one sheet of recording paper. In this case, the recording paper is first fed to a printing means, and after printing is effected on one side thereof, the recording paper is inverted and fed again to the printing means. As an example of an apparatus for supplying the recording paper for this purpose, an apparatus having the following is known: a paper supply tray for stacking and accommodating new recording paper for which printing has not been effected; a first conveyance means for supplying the sheets of recording paper on the paper supply tray one by one to the printing means; an inverting device for inverting the recording sheet which has been supplied to the printing means and on one side of which printing has been effected; an intermediate tray for receiving the inverted recording paper; and a second conveyance means for supplying the sheets of recording paper on the intermediate tray one by one to the printing means.
With the above described conventional apparatus, however, it is necessary to provide a special arrangement for duplex printing, including the intermediate tray and the second conveyance means. Consequently, there are drawbacks in that the number of parts used is numerous, the assembly is cumbersome, and production costs are high.